Predictions of non-equilibrium phase transition in a model low-pressure steam turbine

Abstract

An Eulerian-Eulerian multi-phase computational fluid dynamics model for predicting phase transition under non-equilibrium conditions in the low-pressure stages of a steam turbine is presented. In a novel way the model introduces dispersed liquid phases into the solution according to phase transition type and location in the turbine. Such an approach provides added information on the location and extent of phase transition regions, including associated droplet size, number, and wetness distributions. The model provides a mass weighted size distribution throughout the turbine with a resolution depending on the number of phases chosen. The study presents examples of the models usefulness in isolating phase transition activity and growth at design and off-design conditions. Comparison against results based on equilibrium phase transition in the turbine is provided for verification and discussion. Validation against measured droplet and flow data from the model turbine is also discussed.